Louisville Metropolitan Sewer Districts’ (MSD) Municipal Separate Storm Sewer System (MS4) is regulated by the Kentucky Pollutant Discharge Elimination System (KPDES) Permit, as required by the Clean Water Act, which is administered by Kentucky Division of Water. As a part of MSD’s MS4 permit, post-construction is required for all new development and redevelopment with a disturbed area equal to or greater than one (1) acre within the City of Louisville & Jefferson County, Kentucky. Post-construction minimum control measures and green infrastructure have been required since 2013. This presentation will discuss the evaluation of the Green Infrastructure (GI) program, with the most recent updates to the certification of Water Quality Unit (WQU) requirements, GI practice case studies, fee-in-lieu of (FILO) program goals, regulatory requirements, tracking of GI practices and future funding challenges and opportunities anticipated for this program. Since the implementation of the August 1, 2013, WDR amendment to include post-construction control measures and green infrastructure, Louisville MSD has approved installation of over 1,300 post-construction measures that include green infrastructure practices at new development or redevelopment sites throughout Louisville and Jefferson County. As the post construction industry has grown and adapted to new regulations, politics, technology and asset management understanding, MSD’s program has worked to change and adapt to these challenges. This presentation will explore the lessons learned, emerging challenges and successes associated with MSD’s post construction program.